3-Furyl beta-chalcogencycloaklyl sulfides

ABSTRACT

3-Furyl beta-chalcogencycloaklyl sulfides having the structure: ##STR1## wherein X is a chalcogen selected from the group consisting of oxygen and sulfur; and R 2  and R 3  are each selected from the group consisting of methyl and hydrogen, at least one of R 2  or R 3  being methyl, the moieties X and S being in a trans relationship, such 3-furyl beta-chalcogencycloalkyl sulfides being useful in altering, modifying or enhancing the organoleptic properties of foodstuffs.

This application is a continuation-in-part of U.S. application for Letters Patent Ser. No. 542,830, filed on Jan. 21, 1975 now U.S. Pat. No. 3,933,863 issued on Jan. 20, 1976.

BACKGROUND OF THE INVENTION

The present invention relates to novel 3-furyl beta-chalcogencycloalkyl sulfides.

Artificial flavoring agents for foodstuffs have received increasing attention in recent years. In many areas, such food flavoring agents are preferred over natural flavoring agents at least in part because of the uniform flavor that may be so obtained. For example, natural food flavoring agents such as extracts, essences, concentrates and the like are often subject to wide variation due to changes in the quality, type and treatment of the raw materials. Such variation can be reflected in the end product and results in unreliable flavor characteristics and uncertainey as to consumer acceptance and cost. Additionally, the presence of the natural product in the ultimate food may be undesirable because of increased tendency to spoil. This is particularly troublesome in convenience and snack food usage where such products as dips, soups, chips, prepared dinners, canned foods, sauces, gravies and the like are apt to be stored by the consumer for some time prior to use.

The fundamental problem in preparing artificial flavoring agents is that of achieving as nearly as possible a true flavor reproduction. This generally proves to be a difficult task since the mechanism for flavoring development in many foods is not understood. This is noteable in products having sweet, meaty and roasted meat flavor and nut-like flavor characteristics. It is also noteable in products having vegetable-like and hydrolyzed vegetable protein-like and anise-like flavor characteristics.

Reproduction of nutty and sweet-meaty flavors and aromas and hydrolyzed vegetable protein-like flavors and aromas has been the subject of the long and continuing search by those engaged in the production of foodstuffs. The severe shortage of foods, especially protein foods, in many parts of the world has given rise to the need for utilizing non-meat sources of proteins and making such proteins as palatable and as meat-like as possible. Hence, materials which will closely simulate or exactly reproduce the flavor and aroma of roasted meat and sweet, meat products, vegetable products and products having nut-like taste are required.

Moreover, there are a great many meat containing or meat based foods presently distributed in a preserved form. Examples being condensed soups, dry-soup mixes, dry meat, freeze-dried or lyophilized meats, packages gravies and the like. While these products contain meat or meat extracts, the fragrance, taste and other organoleptic factors are very often impaired by the processing operation and it is desirable to supplement or enhance the flavors of these preserved foods with versatile materials which have either roasted meat or sweet meat or vegetable-like or nut-like nuances.

U.S. Pat. No. 3,666,594 provided materials having such desirable meat, roast meat and roasted fragrance and flavor notes. Such materials are organic oxygen containing heterocyclics wherein the second carbon atom from the oxygen atom contains a sulfur substituent and included 3-thia furan compounds having the structure: ##STR2## wherein R₆, R₇, R₈ and R₉ are the same or different alkyl or hydrogen. The process disclosed in this patent indicated that such furan 3-thiols and alkyl substituted furan 3-thiols can be produced by the reaction of an appropriate dihydro furanone-3-or tetrahydro furanone-3-with hydrogen sulfide in the presence of anhydrous hydrogen chloride at temperatures of -60° to -100° C.

Nothing in the prior art, however, sets forth implicitly or explicitly the 3-furyl beta-chalcogencycloalkyl sulfides of our invention and their unique and advantageous and unobvious flavor properties.

THE INVENTION

The present invention provides novel 3-furyl beta-chalcogencycloalkyl sulfides useful for altering, modifying or enhancing the organoleptic properties of foodstuffs.

The novel compounds are 3-furyl beta-chalcogencycloalkyl sulfides having the structure: ##STR3## wherein X is a chalcogen selected from the group consisting of oxygen and sulfur; and R₂ and R₃ are each selected from the group consisting of methyl and hydrogen, at least one of R₂ or R₃ being methyl, the moieties X and S being in a "trans" relationship.

Thus, 3-furyl beta-chalcogencycloalkyl sulfides contemplated within the scope of our invention, are for example:

    ______________________________________                                         3-Furyl Beta-Chalcogencycloalkyl                                               Sulfide Compound     Structure                                                 ______________________________________                                         Trans (2-hydroxy cyclohexyl) (2- methyl-3-furyl) sulfide                                             ##STR4##                                                 Trans (2,5-dimethyl-3-furyl) (2-hydroxy cyclohexyl) sulfides                                         ##STR5##                                                 Trans (2-methyl-3-furyl) (2-mer- capto cyclohexyl) sulfide                                           ##STR6##                                                 Trans (2,5-dimethyl-3-furyl) (2- mercapto cyclohexyl) sulfide                                        ##STR7##                                                 Trans (2-methyl-4-furyl) (2- hydroxy cyclohexyl) sulfide                                             ##STR8##                                                 Trans (2-methyl-4-furyl) (2- mercapto cyclohexyl) sulfide                                            ##STR9##                                                 ______________________________________                                    

The 3-furyl beta-chalcogencycloalkyl sulfides of our invention may be produced according to a process which comprises the steps of:

i. Carrying out a reaction of a 3-mercapto furan with a thiirane or epoxide to form the compounds of our invention according to the following reaction: ##STR10##

ii. Physically separating said 3-furyl beta-chalcogencycloalkyl sulfide from the reaction mass,

wherein X, R₂ and R₃ are defined as above, and X and S being in a "trans" relationship to one another.

The following table sets forth examples of specific reactants and the resulting products produced using the process of our invention:

                                      TABLE I                                      __________________________________________________________________________     Thiirane or                                                                               3-Furan Thiol                                                                           3-Furyl Beta-Chalcogencycloalkyl                           Expoxide Reactant                                                                         Reactants                                                                               Sulfide Compound  Structure                                __________________________________________________________________________     1,2-epoxycyclo- hexane                                                                    2-methyl-3- furan thiol                                                                 Trans (2-hydroxy cyclohexyl) (2- methyl-3-furyl)                               sulfide                                                                                           ##STR11##                               1,2-epoxycyclo- hexane                                                                    2,5-dimethyl- 3-furan thiol                                                             Trans (2,5-dimethyl-3-furyl) (2-hydroxy cyclohexyl)                            sulfides                                                                                          ##STR12##                               1,2-cyclohexane- thiirane                                                                 2-methyl-3- furan thiol                                                                 Trans (2-methyl-3-furyl)(2-mer- capto cyclohexyl)                              sulfide                                                                                           ##STR13##                               1,2-cyclohexane- thiirane                                                                 2,5-dimethyl- 3-furan thiol                                                             Trans (2,5-dimethyl-3-furyl)(2- mercapto cyclohexyl)                           sulfide                                                                                           ##STR14##                               1,2-epoxycyclo- hexane                                                                    5-methyl-3- furan thiol                                                                 Trans (2-methyl-4-furyl)(2- hydroxy cyclohexyl)                                sulfide                                                                                           ##STR15##                               1,2-cyclohexane- thiirane                                                                 5-methyl-3- furan thiol                                                                 Trans (2-methyl-4-furyl)(2- mercapto cyclohexyl)                               sulfide                                                                                           ##STR16##                               __________________________________________________________________________

The reaction of our invention, in order to proceed in a practical manner, should take place in the presence of a basic catalyst, preferably a lower alkyl amine such as diethyl amine, triethyl amine or trimethyl amine.

The reaction is also best carried out in the presence of a non-reactive solvent such as a lower alkanol, preferably methanol, ethanol or n-propanol.

The mole ratio of reactants, the 3-furan thiol: the epoxide or thiirane may vary from 1:1 to 5:1 with a preferred ratio of 3-furan thiol:epoxide or thiirane of 2:1.

The reaction temperature may vary from 50° up to 80° C, the time of reaction being a function of the reaction temperature, with lower reaction temperatures giving rise to longer periods of time of reaction and higher temperatures of reaction giving rise to much shorter periods of time of reaction. Thus, for example, it is preferred to run the reaction for optimum yield at a temperature in the range of 50°-65° C for a period of time for approximately 45 minutes.

The reaction is preferably carried out at atmospheric pressure but pressures greater than atmospheric, e.g., 5 atmospheres may be used without detrimentally affecting the yield of product of the time of reaction which is required to attain such yield.

At the end of the reaction, the reaction product is extracted from the reaction mass using a non-reactive solvent, e.g., methylene dichloride, after the reaction mass is first quenched with water and neutralized with aqueous acid. The solvent extract is then dried, concentrated and distilled preferably by means of vacuum distillation.

The following reactions are illustrative of the process used to produce the novel products of our invention: ##STR17##

The 3-furyl beta-chalcogencycloalkyl sulfides of our invention produced in this manner have useful organoleptic properties giving rise to their use as food-stuff flavors as set forth in an illustrative manner in the following table:

                                      TABLE II                                     __________________________________________________________________________     3-Furyl Beta-Chalcogencycloalkyl                                               Sulfide Compound  Structure  Flavor Properties                                 __________________________________________________________________________     Trans (2-hydroxy cyclohexyl) (2-methyl-3-furyl) sulfide                                           ##STR18##                                                                                 ##STR19##                                        Trans (2,5-dimethyl-3-furyl) (2-hydro cyclohexyl) sulfide                                         ##STR20##                                                                                 ##STR21##                                        __________________________________________________________________________

Thus, the 3-furyl beta-chalcogencycloalkyl sulfides according to the present invention can be used to alter, vary, fortify, modify, enhance or otherwise improve the organoleptic properties, including flavor and/or aroma, of a wide variety of materials which are ingested, consumed, or otherwise organolepticaly sensed.

The terms "alter" and "modify" in their various forms will be understood herein to mean the supplying or imparting a flavor character or note to an otherwise bland, relatively tasteless substance, or augmenting an existing flavor characteristic where the natural flavor is dificient in some regard, or supplementing the existing flavor or aroma impression to modify the organoleptic character. The materials which are so altered are generally referred to herein as consumable materials.

The term "enhance" in its various forms will be understood herein to mean the intensification of a given flavor and/or aroma "nuance" or "note" in a food flavor composition and/or in a foodstuff without changing the type or quality of said flavor or aroma nuance or note.

Such 3-furyl beta-chalcogencycloalkyl sulfides are accordingly useful in flavoring compositions. Flavoring compositions are herein taken to mean those which contribute a part of the overall flavor impression by supplementing or fortifying a natural or artificial flavor in a material, as well as those which supply substantially all the flavor and/or aroma character to a consumable article.

The term "foodstuff" as used herein includes both solid and liquid ingestible materials for man or animals, which materials usually do, but need not, have nutritional value. Thus, foodstuffs includes meats, gravies, soups, convenience foods, malt and other alcoholic or non-alcoholic beverages, milk and dairy products, nut butters such as peanut butter and other spreads, seafoods including fish, crustaceans, mollusks and the like, candies, breakfast foods, baked goods, vegetables, cereals, soft drinks, snack foods, dog and cat foods, other veterinary products, and the like.

When the 3-furyl beta-chalcogencycloalkyl sulfides according to this invention are used in a food flavoring composition, they can be combined with conventional flavoring materials or adjuvants. Such co-ingredients or flavoring adjuvants are well known in the art for such use and have been extensively described in the literature. Apart from the requirement that any such adjuvant material be ingestibly acceptable, and thus non-toxic or otherwise non-deleterious, conventional materials can be used and broadly include other flavor materials, vehicles, stabilizers, thickeners, surfact active agents, conditioners and flavor intensifiers.

Examples of preferred co-flavoring adjuvants are:

Methyl thiazole alcohol (4-methyl-5-beta-hydroxyethyl thiazole);

2-Methyl butanethiol;

4-Mercapto-2-butanone;

3-Mercapto-4-pentanone;

1-Mercapto-2-propanone;

Benzaldehyde;

Furfural;

Furfural alcohol;

2-Mercapto propionic acid;

Alkyl pyrazine;

Methyl pyrazine;

2-Ethyl-3-methyl pyrazine;

Tetramethyl pyrazine;

Polysulfides;

Dipropyl disulfide;

Methyl benzyl disulfide;

Alkyl thiophenes;

2-Butyl thiophene;

2,3-Dimethyl thiophene;

5-Methyl furfural;

Acetyl furan;

2,4-Decadienal;

Guiacol;

Phenyl acetaldehyde;

δ-Decalactone;

d-Limonene;

Acetoin;

Amyl acetate;

Maltol;

Ethyl butyrate;

Levulinic acid;

Piperonal;

Ethyl acetate;

n-Octanal;

n-Pentanal;

Hexanal;

Diacetyl;

Monosodium glutamate;

Sulfur-containing amino acids;

Cysteine;

Hydrolyzed vegetable protein;

2-Methylfuran-3-thiol;

2-Methyldihydrofuran-3-thiol;

2,5-Dimethylfuran-3-thiol;

Hydrolyzed fish protein; and

Tetramethyl pyrazine

The 3-furyl beta-chalcogencycloalkyl sulfides or the compositions incorporating them, as mentioned above, can be combined with one or more vehicles or carriers for adding them to the particular product. Vehicles can be edible or otherwise suitable materials such as ethyl alcohol, propylene glycol, water and the like. Carriers include materials such as gum arabic, carrageenan, other gums and the like. The 3-furyl beta-chalcogencycloalkyl sulfides according to this invention can be incorporated with the carriers by conventional means such as spray-drying, drum-drying and the like. Such carriers can also include materials for coscervating the 3-furyl beta-chalcogencycloalkyl sulfides (and other flavoring ingredients, as present) to provide encapsulated products. When the carrier in an emulsion the flavoring composition can also contain emulsifiers such as mon- and diglycerides or fatty acids and the like. With these carriers or vehicles, the desired physical form of the composition can be prepared.

The quantity of 3-furyl beta-chalcogencycloalkyl sulfides utilized should be sufficient to impart the desired flavor characteristic to the product, but on the other hand, the use of an excessive amount of the derivative is not only wasteful and uneconomical, but in some instances too large a quantity may unbalance the flavor or other organoleptic properties of the product consumed. The quantity used will vary depending upon the ultimate foodstuff; the amount and type of flavor initially present in the foodstuff; the further process or treatment steps to which the foodstuff will be subjected; regional and other preference factors; the type of storage; if any, to which the product will be subjected; and the preconsumption treatment, such as baking, frying, and so on, given to the product by the ultimate consumer. Accordingly, the terminology "effective amount" and "sufficient amoung" is understood in the context of the present invention to be quantitatively adequate to alter the flavor of the foodstuff.

It is accordingly preferred that the ultimate compositions contain from about 0.02 parts per million (ppm) to about 250 ppm of 3-furyl beta-chalcogencycloalkyl sulfides or mixtures thereof. More particularly, in food compositions it is desirable to use from about 0.03 ppm to 100 ppm for enhancing flavors and in certain preferred embodiments of the invention, from about 0.05 to 50 ppm of the derivatives are included to add positive flavors to the finished product.

The amount of 3-furyl beta-chalcogencycloalkyl sulfides or mixtures thereof of our invention to be utilized in flavoring compositions can be varied over a wide range depending upon the particular quality to be added to the foodstuff. Thus, amounts of one or more derivatives according to the present invention of from about 0.5 ppm up to 80 or 90 percent of the total flavoring composition can be incorporated in such compositions. It is generally found to be desirable to include from about 1 ppm up to about 0.1 percent of the 3-furyl beta-chalcogencycloalkyl sulfides in such compositions.

The following examples are given to illustrate embodiments of the invention as it is preferably preferred to practice it. It will be understood that these examples are illustrative and the invention is not to be considered as restricted thereto except as indicated in the appended claims.

All parts, proportions, percentages, and ratios herein are by weight unless otherwise indicated.

EXAMPLE I PREPARATION OF TRANS (2-HYDROXY CYCLOHEXYL) (2-METHYL-3-FURYL) SULFIDE

Reaction: ##STR22## A test tube equipped with a magnetic stirrer is immersed in a water bath. Into the test tube are charged 1 ml of methanol, 4 drops of diethyl amine, 20 drops of 2-methyl-3-furanthiol, and 12 drops of cyclohexene oxide. The reaction mass is heated with stirring on a hot plate at about 60° C for 2 hours. The reaction mass is then concentrated in vacuo on a rotary evaporator. The product is isolated by preparative GLC (Conditions: 8 × 1/4 inches 25% SE-30 column; 120° C programmed at 6° C/min).

Mass spectral, infrared and NMR analyses confirm the structure as being: ##STR23## Mass spectral analysis is as follows:

    ______________________________________                                                m/e                                                                            212 parent ion       43                                                        114                  41                                                         81                  28                                                 ______________________________________                                    

This material has a pork, bacon rind character.

EXAMPLE II PREPARATION OF TRANS (2,5-DIMETHYL-3-FURYL (2-HYDROXY CYCLOHEXYL SULFIDE

Reaction: ##STR24## A test tube equipped with a magnetic stirrer is immersed in a water bath. Into the test tube are charged 1 ml of methanol, 4 drops of diethyl amine, 20 drops of 2,5-dimethyl-3-furanthiol, and 12 drops of cyclohexene oxide. The reaction mass is heated and stirred on a hot plate at about 60° C for 2 hours. The reaction mass is then concentrated in vacuo on a rotary evaporator. The product is isolated by preparative GLC (Conditions: 8 × 1/4 inches 25% SE-30 column; 120° C programmed at 6° C/min).

Mass spectral, infrared and NMR analyses confirm the structure as being: ##STR25## Mass spectral analysis is as follows:

    ______________________________________                                                m/e                                                                            226 parent ion       41                                                        128                  81                                                         43                  28                                                         95                                                                     ______________________________________                                    

This material has a meaty, pork and yeast character.

EXAMPLE III

Trans (2-hydroxy cyclohexyl) (2-methyl-3-furyl) sulfide prepared according to the process of Example I is added to a 2% solution of Wyler's "Beef Flavored Instant Bouillon" (manufactured by Wyler Foods, Division of Borden, Inc., Chicago, Illinois, U.S.A.).

(Ingredients: salt, hydrolyzed vegetable protein, malto dextrin, sugar, beef fat, water, monosodium glutamate, flavorings, corn sugar, beef extract, caramel color, hydrogenated vegetable fat and U.S. certified food color)

at the rate of 1 ppm. This chemical adds a bacon characteristic to the beef broth.

EXAMPLE IV

Trans (2,5-dimethyl-3-furyl) (2-hydroxy cyclohexyl) sulfide prepared according to the process of Example II is added to a 2% solution of Wyler's "Beef Flavored Instant Bouillon" (manufactured by Wyler Foods, Division of Borden, Inc., Chicago, Illinois, U.S.A.).

(Ingredients: salt, hydrolyzed vegetable protein, malto dextrin, sugar, beef fat, water, monosodium glutamate, flavorings, corn sugar, beef extract, caramel color, hydrogenated vegetable fat, U.S. certified food color)

at the rate of 2 ppm. This chemical adds a cooked pork note to the beef broth. 

What is claimed is:
 1. A 3-furyl beta-chalcogencycloalkyl sulfide having the structure: ##STR26## wherein X is a chalcogen selected from the group consisting of oxygen and sulfur; and R₂ and R₃ are each selected from the group consisting of methyl and hydrogen, at least one of R₂ or R₃ being methyl, X and S being in a "trans" relationship to one another.
 2. The 3-furyl beta-chalcogencycloalkyl sulfide compound of claim 1 wherein X is sulfur.
 3. The 3-furyl beta-chalcogencycloalkyl sulfide compound of claim 1 wherein X is oxygen.
 4. The 3-furyl beta-chalcogencycloalkyl sulfide compound of claim 2 wherein R₂ is methyl and R₃ is hydrogen.
 5. The 3-furyl beta-chalcogencycloalkyl sulfide compound of claim 3 wherein R₂ is methyl and R₃ is hydrogen.
 6. The 3-furyl beta-chalcogencycloalkyl sulfide compound of claim 2 wherein R₂ and R₃ is each methyl.
 7. The 3-furyl beta-chalcogencycloalkyl sulfide compound of claim 3 wherein R₂ and R₃ is each methyl. 